The present invention relates to a multi-part piston for an internal combustion engine, having an upper piston part and a lower piston part, whereby the upper piston part has a piston crown, a circumferential top land, as well as a circumferential ring belt, whereby the upper piston part and the lower piston part are connected with one another by means of attachment means and form a circumferential cooling channel.
In the case of such known multi-part cooling channel pistons, the problem exists of reliably connecting the upper piston part and the lower piston part with one another, while avoiding stresses. Furthermore, optimization of the cooling effect of the cooling oil contained in the cooling channel is aimed at. The cooling oil circulates in the cooling channel and is moved as a result of the shaker effect that is brought about by the piston movement. In DE 102 44 512 A1, it is proposed to provide the circumferential cooling channel with bores that are directed toward the piston crown, in order to achieve a better distribution of the cooling oil. However, in the case of pistons that are subject to great stress, in particular, the heat dissipation brought about by the movement of the cooling oil is not sufficient.
The present invention is therefore based on the task of creating a multi-part piston of the type indicated, having an improved cooling effect of the cooling oil that circulates in a cooling channel, in which piston the upper piston part and the lower piston part are reliably connected with one another.